The present invention relates to an improved insole construction having extremely high shock absorbing capabilities.
By way of background, numerous types of insoles have been used in the past. These insoles usually were fabricated from rubber, cork or polyurethane materials, and some prior insoles consisted of a plurality of layers of materials. However, prior insoles, even those comprising a plurality of layers, still transmitted a considerable amount of shock upwardly to the foot and beyond.
Studies have shown that the foot and lower leg are subjected to relatively large forces. In fact, it has been found that walking on a hard surface produces decelerations as high as 30 G in the heel of a hard leather shoe. The impacting shock waves transmitted to the foot during walking, jogging and engaging in sports, such as aerobics and racquet sports, are further transmitted upwardly through the flesh and bones of the body. Unabsorbed shock forces can contribute to various types of medical problems, such as shin splints, leg joint and hip problems and lower back pains. In addition, to vibrational shock forces, the feet are subjected to pressure and skin shear, the latter resulting from horizontal and rotational foot movements.
In the past it has been known that a viscoelastic material can absorb forces generated at the foot interface, and the use of such a material in the shoe improved both comfort and protection against related health problems. It is with an extension of the foregoing knowledge that the present invention is concerned.